I don't find it difficult because I do contribute the best I can, but I can't please everyone,
Just have to support you on this, the only reason people find it difficult is because they joined the forum with the wrong mindset. Ask yourself what makes a good forum user. It isn't rocket science to be one as all the attributes are quite easy to possess, some times you just have to fake it until it becomes a part of you. We have those that are working underground (spam hunters) but someone might review their account and place them below others just because they aren't getting merit like others as that is what most forum users now use to judge who is or isn't a quality forum user. It isn't that difficult to be useful to the forum.
Exactly, everyone is different, it's like you are working in a company (signature campaign) that has a lot of employees, of course among the employees, there are best, average, and poor employees in terms of performance, and it's the campaign managers job to decide which to promote or to retain in a company.
Being just an ordinary member is different from being a campaign because if you are in a campaign, you have to follow the rules of the campaign and at the same time you need to follow the forum rules which sometimes put more pressure on your compared if you are a member without a campaign.